Conventionally, typical tilting-ladle-type automatic pouring methods are known as disclosed in Patent Literature 1, 2, and 3.
In the method in Patent Literature 1, a ladle is inversely tilted when it pours molten metal at an arbitrary rate of pouring. Then, a predicted volume of the molten metal poured until draining is derived based on the volume of the molten metal poured during the inverse tilting step, while the rate of pouring is derived. The predicted volume of the molten metal poured until draining when the pouring begins at the derived rate of pouring is sequentially compared with the remaining volume of pouring, which denotes the difference between the target volume of the molten metal poured and the current volume of the molten metal poured. The ladle is then inversely tilted when the remaining volume is less than the predicted volume of the molten metal poured until draining to complete pouring.
The method of Patent Literature 2 uses a servo motor that is controlled by means of a computer that is preconfigured to contain a program. In this method, a ladle holding molten metal is tilted to a side of a bank of the ladle to rapidly raise the molten-metal level to a target level to begin pouring the molten metal under conditions to prevent the molten metal from overflowing from the bank. The ladle is continuously tilted to the side of the bank to eject the molten metal therein such that the outflowed volume of the molten metal from the ladle substantially equals the inflow volume of the molten metal into a mold, when the pouring begins and at the end of the startup, while the molten-metal level in the bank is maintained at a substantially constant level. The ladle is then tilted to the opposite side of the bank to prevent the molten metal in the ladle from sloshing while the molten metal is drained to complete pouring.
In the method of Patent Literature 3, a molten metal level in a ladle when it is reversely tilted is derived based on a molten metal level that is located above the tapping hole of the ladle and lowers by stopping the forward tilting of the ladle and a molten-metal level that lowers by beginning the reverse tilting of the ladle. Using (1) a relationship between the derived molten-metal level and the filling weight of the molten metal poured into a mold from the ladle and (2) a model of the flow rate of the molten metal poured for the filling weight of the molten metal that flows from the ladle into the mold, the final filling weight of the molten metal poured from the forward tilting of the ladle to the reverse tilting of the ladle is predicted by assuming that the final filling weight is the sum of the filling weight of the molten metal poured when the ladle begins the inverse tilting and the filling weight of the molten metal poured after the ladle begins the inverse tilting. Then, a determination is made whether the predicted final filling weight of the molten metal poured equals a predetermined final filling weight. Based on the result of the determination, the reverse tilting motion of the ladle begins.